Could finally find time to make some pictures to try and help (cf. attached image).
As I haven't bigger papers at hand, for the pictures, I only folded the part where you are stuck: the upper-right of the green fat line in my picture 46.
Step 46 is "just" a spread squash fold - I guess you managed to do it if you are stuck in step 47 (if not, please tell me!).

Beginning of step 47 (picture 47-1); you need to open a bit the bottom part to pull some paper out, as seen in 47-2. The yellow and green lines correspond to the edges as seen in diagram step 47. Model won't lie flat.

For step 48:
- invert the mountain fold shown in green in picture 47-2 so that it becomes a valley fold (the valley fold in diagram step 48),
- add the red mountain fold as seen in picture 48-1.
(The purple line, which aligns with the yellow mountain fold, will become a mountain fold too.)

48-2 shows the step almost done (the model still won't be flat at the end of that step).

Hopefully, it will help you a bit.
Please tell me if the explanation is not clear enough (and also if you managed to do it too)!